The unintentional uncoupling or separation of railway cars such as freight car air brake end hoses, while trains are in motion, causes an emergency application of the train's air brakes, an event known as an Undesired Emergency, or UDE. Such a brake application can result in a number of potentially negative consequences. Such consequences include train delays, and not only to the train involved with a UDE, but also to other trains both behind and in front of the train that has the uncoupled air brake line. Urgent train stops also cause possible freight car structural damage and component breakage, i.e., couplers, knuckles, pins, keys and cushion units, etc. They can also damage the commodity carried by such freight cars. Such uncoupling, therefore, results in increased costs due to the re-crewing of trains, overtime to repair cars on line, and loss of productivity.
Such accidental uncoupling also can result in negative impact on the carrier's ability to meet customer commitments, resulting in customer complaint and possible loss in revenue. There are also safety concerns of crew members who must walk along the train to assess the cause of the UDE, which is particularly dangerous in severe weather conditions.
Public inconvenience due to potentially blocked public crossings, particularly in densely populated areas, is another resulting problem. There is also the potential for train derailment. Accordingly, the uncoupling or separation of a railcar air brake end hose can result in serious consequences.
The separation of air brake end hoses can occur when the relative position of the gladhands which interconnect the end hoses of two coupled cars changes due to excessive slack in the end of car components.
On freight cars equipped with cushioned units, the air brake end hose is connected to the intermediate air brake hose by means of a rigid or train line support union, which is supported either by the conventional train line bracket or fixed trolley rod arrangement. The conventional train line bracket is attached to the cushion unit yoke through the use of a bolt and a locknut to secure it in place. The intermediate hose, which supplies pressurized air from the angle cock valve to the freight car brake system, is connected to the car end hose through a rigid train line support union that is secured to the conventional train line bracket.
The conventional train line bracket moves with the yoke as the cushion unit moves inboard and outboard to absorb the energy imparted by train action when in service. Train action causes wear in end of car components. A disadvantage of this design is its inability to compensate for end of car component wear. This wear causes excessive slack between the coupler and the yoke, thereby affecting the performance of the car end hoses. This can cause two coupled car end hoses to become kinked or separated. When car end hoses separate, the train will go into a UDE, and when they kink, brakes are lost from the kinked hose back to the tail end of the train.
The fixed trolley rod arrangement presently applied on car ends is welded to the freight car structure. This design compensates for end of car component wear by incorporating a long rod along which the train line support union freely travels, thereby maintaining the alignment of the car end hoses. However, as the fixed trolley does not move with the cushion unit, it needs to have enough travel to extend beyond the car end to allow for extreme inboard or outboard coupler movement. This extension makes the device susceptible to damage and may cause it to interfere with other end of car components. U.S. Patent Publication No. 2004/0155005 teaches a strap suspension assembly with a swivel displaceable on a fixed rod which is not coupled to the yoke.